MRI technicians operate magnetic resonance imaging (MRI) scanners. MRI scanners use strong magnetic fields and radio frequencies to create 3D images of a patient's body tissues, which physicians then use as an aid to diagnosis. Individuals wishing to seek careers in the field can enroll in MRI technology certificate, diploma or associate's degree programs. Licensing is required by most states. Many MRI technology programs are open only to students who have been trained as radiologic technicians or technologists; these individuals often hold certification in radiologic technology.